Genetic counseling: Choroid Plexus Cysts on Ultrasound
Choroid Plexus Cysts on Ultrasound Introduction and Contracting *Ask how the pregnancy is going *Ask about dates *Explain the session **Getting family hx/pregnancy hx **Talking about what a choriod plexus cyst is and what it means for the pregnancy, testing that may be offered **What questions do you have? Pregnancy hx *Any illnesses? *Any infections/exposures? *Any medications? *Verify dates *Screening tests up to now…ultrasounds? Triple screen test? Family hx (probably at end of session) *Get two generation pedigree *Determine any risks to pregnancy *Specify any particular ethnic concerns as well Choriod Plexus Cysts (probably at beginning of session) *What have you heard about them? *The Choroid plexus **A spongy layer of cells and blood vessels along the edge of the ventricles (pockets or spaces in the brain **Produces the cerebrospinal fluid that fills the ventricles and provides a cushion to the brain and spinal cord. **Development starts at 6th week **By 9th weeks the choroids plexus fills ~75% of lateralventricles **Starts to slowly decrease in size and by 20th week the choriod plexus has assumed its adult form *Choriod Plexus Cysts **Description ***Caused by folding of the spongy layer = trapping fluid in the area ***BENIGN!!! They do not cause any problems for the fetus ***Usually <1cm in size ***Can be unilateral or bilateral ***Usually can be detected by 11th week of pregnancy ***usually resolve by the 24-28th week of pregnancy **Incidence ***Found in 1% of pregnancies scanned between the 16th - 20 week. ***Found in 50% of autopsies (fetuses, adults, elderly) *Association with chromosomal abnormalities **HIGHLY controversial **Trisomy 18 ***~45% of fetuses with Trisomy 18 had choriod plexus cysts ****does not depend on gestational age, unilateral or bilateral or size ***1-2% risk of a chromosomal abnormality when CPC are found. Most likely Trisomy 18 if anything ***TRISOMY 18 the syndrome ****Describe genes and chromosomes ****1/3000-1/7000 live births ****most do not survive to term ****if live birth, usually die in days,weeks following birth ****90% die within the first year of live ****severe congenital anomalies **90% heart defects ****severe mental retardation ***70-77% babies with Trisomy 18 will have other findings on ultrasound (some studies say ~100% after 24 weeks) ****clenched fists ****heart defects ****rocker-bottom feet ****omphalocele ****hydrocephalus **VERY CONTROVERSIAL- relation to Down syndrome (thought to be coincidental by most authors) ***Very rarely seen to be related to CPC cysts ***1/660 live births ***DS - the syndrome ****Mild-moderate MR ****Heart problems in 40% ****Characteristic facial features ***Ultrasound findings ****Echogenic bowel ****Femur length ****Nuchal fold thickness Discussion of triple screen results (if they are present) *SCREENING test - NOT diagnostic *Measuring three values of proteins in the mother'sblood *They are produced by the baby in its liver *MoM values of 1.0 are the standard *Maternal age and gestational age are considered *For risks associated with Trisomy 18 = expect all three values to be low *Your results show (no/an) increased risk over the general pop of mothers who are your gestational age. Risk of having a baby with Trisomy 18 *Consider maternal age *Consider CPC *Consider triple screen results *Consider presence of other markers on ultrasound *USE CHART (see attached or ask Kris for a copy of hers) Testing Offered *Detailed ultrasound to look for other markers (previously discussed) *Amniocentesis **Risk 1/200 **Determines presence or absence of aneuploidy **Does not guarantee a healthy baby **Some centers debate about offering based solely on CPC Important Points *18% of unaffected fetuses will have more than just CPC on ultrasound!!!!! Notes The information in this outline was last updated in 2001. Material obtained under GFDL Licence from http://en.wikibooks.org/wiki/Handbook_of_Genetic_Counseling